Following the Fall of France in 1940, the nation’s industry was fundamentally reorganised under the Vichy regime. This thesis traces the history of the keystones of this New Industrial Order, the Organisation Committees, by focusing on the organisation of the French steel industry between the end of the Third Republic in 1940 and the establishment of the Fourth Republic in 1946. It challenges traditional views by showing that the Committees were created largely to facilitate economic collaboration with Nazi Germany. It also demonstrates that these institutions were run by a new group of technocratic managers from French industry and that they willingly oversaw production for the Third Reich insofar as it remained advantageous to French steel firms. By extending the period of study beyond the end of the Vichy regime, this thesis casts light on why the leaders of the Resistance decided to maintain these problematic institutions and provides the first detailed account of how the bodies were reformed following the Liberation of France. Finally, it reveals that although the Organisation Committees were formally abolished in 1946, Jean Monnet created parallel bodies, named Modernisation Commissions, which took over the functions and carried on the work of Vichy’s Committees under the auspices of the Monnet Plan. By demonstrating the continuities of institutions and individuals in French industrial organisation from 1940 to 1946, or l’entre-deux-républiques, this thesis contributes to the history of Vichy and post-war France and re-evaluates the origins of the Monnet Plan and of the European Coal and Steel Community, the forerunner to today’s European Union.